Clean up documentation

[dholstius]

devtools::check() reports the following:

> checking for missing documentation entries ... WARNING
  Undocumented code objects:
    ‘convert_qty’ ‘maximum’ ‘minimum’ ‘most_frequent’ ‘rank_fraction’
    ‘rank_product’ ‘scale_emissions_by’ ‘scale_throughputs_by’
  All user-level objects in a package should have documentation entries.
  See chapter ‘Writing R documentation files’ in the ‘Writing R
  Extensions’ manual.

> checking for code/documentation mismatches ... WARNING
  Codoc mismatches from documentation object 'sum_emissions_by':
  sum_annual_emissions_by
    Code: function(input_data, ..., digits = Inf, signif = Inf, verbose =
                   getOption("verbose"))
    Docs: function(...)
    Argument names in code not in docs:
      input_data digits signif verbose
    Mismatches in argument names:
      Position: 1 Code: input_data Docs: ...
  
  Codoc mismatches from documentation object 'sum_quantities_by':
  sum_annual_quantities_by
    Code: function(input_data, ..., digits = Inf, signif = Inf, verbose =
                   getOption("verbose"))
    Docs: function(...)
    Argument names in code not in docs:
      input_data digits signif verbose
    Mismatches in argument names:
      Position: 1 Code: input_data Docs: ...
  
  Codoc mismatches from documentation object 'sum_throughputs_by':
  sum_annual_throughputs_by
    Code: function(input_data, ..., digits = Inf, signif = Inf, verbose =
                   getOption("verbose"))
    Docs: function(...)
    Argument names in code not in docs:
      input_data digits signif verbose
    Mismatches in argument names:
      Position: 1 Code: input_data Docs: ...

> checking Rd \usage sections ... WARNING
  Undocumented arguments in documentation object 'GM'
    ‘x’ ‘na.rm’
  
  Undocumented arguments in documentation object 'apply_scalars'
    ‘input_data’ ‘using’ ‘value_col’ ‘key_col’ ‘join_na’ ‘keep_as’
    ‘verbose’ ‘warn’
  
  Undocumented arguments in documentation object 'bin'
    ‘x’ ‘by’
  
  Undocumented arguments in documentation object 'convert_quantities'
    ‘x’ ‘from’ ‘to’
  
  Undocumented arguments in documentation object 'int'
    ‘...’
  Documented arguments not in \usage in documentation object 'int':
    ‘x’
  
  Undocumented arguments in documentation object 'is_units'
    ‘x’
  
  Undocumented arguments in documentation object 'lerp'
    ‘nm’ ‘extrapolate’ ‘envir’ ‘method’
  
  Undocumented arguments in documentation object 'multiply_each'
    ‘by’
  
  Undocumented arguments in documentation object 'top_q'
    ‘verbose’
  
  Undocumented arguments in documentation object 'total'
    ‘na.rm’ ‘verbose’
  
  Undocumented arguments in documentation object 'total_each'
    ‘digits’ ‘signif’
  
  Undocumented arguments in documentation object 'trim_values'
    ‘x’ ‘below’ ‘above’ ‘replace_with’
  
  Functions with \usage entries need to have the appropriate \alias
  entries, and all their arguments documented.
  The \usage entries must correspond to syntactically valid R code.
  See chapter ‘Writing R documentation files’ in the ‘Writing R
  Extensions’ manual.